The present application claims priority under 35 U.S.C. xc2xa7119 to Korean Application No. 2000-61264, which is hereby incorporated by reference in its entirety for all purposes.
1. Field of the Invention
The present invention relates to a method and an apparatus for manufacturing a semiconductor device, and more particularly to a method of performing a chemical vapor deposition process in such a manner that particles can be prevented from forming on a wafer, and an apparatus for performing the same.
2. Description of the Related Art
Recently, as information media including computers are becoming more widely used, the semiconductor industry has made great strides. From a functional standpoint, a semiconductor device is required to be operated at a high speed and to have large storage capacitance. Accordingly, semiconductor manufacturing techniques are developing to improve integration degree, reliance and response speed of semiconductor devices. Thus, strict requirements are required during performing of semiconductor manufacturing processes, such as chemical vapor deposition, which forms a film on a wafer.
Generally, when a chemical vapor deposition process is carried out, deposition gases (source gas) are introduced into a chamber in which the wafer is placed, and the deposition gases react with each other in the chamber so that a film is deposited on the wafer. However, a part of the deposition gases, which is not reacted during the chemical vapor deposition process, is deposited on sidewalls of the chamber or floats in the chamber after the chemical vapor deposition process has been finished. The deposition gases floating in the chamber or deposited on the sidewalls of the chamber cause the generation of particles. The particles can be dropped onto a wafer newly introduced into the chamber, thereby resulting in ultimate failure of the wafer. For this reason, a cleaning process is carried out in the chamber before a wafer is newly introduced into the chamber.
The cleaning of the chamber is carried out by introducing a cleaning gas capable of etching the particles in the chamber. That is, after introducing the cleaning gas into the chamber, a plasma is formed in the chamber in-situ. Then, after etching the particles by using the cleaning gas, the particles are exhausted from the chamber.
There are known methods for cleaning a chamber by forming plasma in-situ. However, when cleaning of the chamber is carried out by forming plasma in-situ, sidewalls of the chamber can be damaged by physical sputtering, so that the chamber is contaminated. For this reason, a known method comprises forming plasma at an exterior of the chamber using a plasma device, and introducing the radical of the cleaning gas into the chamber so as to clean the chamber.
FIG. 1 shows a conventional apparatus for performing a chemical vapor deposition process. Referring to FIG. 1, the apparatus has a chamber 10 in which the chemical vapor deposition process is carried out. A heater (heating plate) 12 on which a wafer W is placed is installed at an inner lower portion of the chamber 10. A shower 14 for introducing a deposition gas and a cleaning gas into the chamber 10 is provided at an inner upper portion of the chamber 10. A deposition gas supply section 20 is installed at an exterior of the chamber 10 in order to supply the deposition gas into the chamber 10. Since the deposition gas is made by mixing various kinds of gases, the deposition gas supply section 20 includes a plurality of gas supply parts 20a, 20b and 20c corresponding to the kinds of the gases. A gas mixer 16 is connected to the deposition gas supply section 20 so as to mix the gases. The gas mixer 16 is also connected to the chamber 10. Accordingly, the gas supply parts 20a, 20b and 20c supply the gases into the gas mixer 16 via respective valves 22a, 22b and 22c and through a deposition gas supply line 18. Then, the gases are mixed in the gas mixer 16 and introduced into the chamber 10.
In addition, a cleaning gas supply section 28 is provided to supply the cleaning gas into the chamber 10. Since the cleaning gas can be made by mixing various kinds of gases, the cleaning gas supply section 28 includes a plurality of cleaning gas supply parts 28a and 28b corresponding to the kinds of the gases. The cleaning gas supply parts 28a and 28b are connected to a plasma device 26 via respective valves 30a and 30b, and through a cleaning gas supply line 24, so that the cleaning gas supplied from the cleaning gas supply parts 28a and 28b is excited in the plasma device 26. The plasma device 26 is connected to the gas mixer 16, so that the cleaning gas filtered in the plasma device 26 is introduced into the chamber 10 through the gas mixer 16, thereby cleaning the chamber 10.
In order to deposit a film on a wafer by using the chemical vapor deposition apparatus of FIG. 1, the chamber 10 is firstly cleaned before the wafer W is loaded into the chamber 10. The cleaning of the chamber 10 is carried out by introducing the cleaning gas into the chamber 10. The particles deposited on the sidewalls of the chamber 10 and the gas floating in the chamber 10 are etched by the cleaning gas introduced into the chamber 10, and are exhausted out of the chamber 10. After cleaning the chamber 10, the wafer W is loaded in the chamber 10. Then, the deposition gas is introduced into the chamber 10 through the deposition gas supply parts 20a, 20b and 20c, so as to deposit the film on the wafer W.
However, while the deposition process is being carried out, a part of the deposition gas supplied from the deposition gas supply parts 20a, 20b and 20c flows back toward the cleaning gas supply line 24. Since a part of the cleaning gas, which is supplied when the cleaning process is carried out, remains in the cleaning gas supply line 24, the part of the deposition gas which has flowed back reacts with the remaining part of the cleaning gas, so that particles are generated. The particles drop onto the wafer while the deposition process is being carried out, thereby resulting in the ultimate failure of the wafer. In addition, the deposition gas which has flowed back is deposited on the cleaning gas supply line 24, or floats in the cleaning gas supply line 24, to thus contaminate the cleaning gas supply line 24. Accordingly, particles are formed on a wafer which is newly introduced into the chamber for the deposition process.
The present invention is therefore directed to a chemical vapor deposition process and apparatus for performing the same, which substantially overcome one or more of the problems due to the limitations and disadvantages of the related art.
A first object of the present invention is to provide a chemical vapor deposition process for reducing particles formed on a wafer.
A second object of the present invention is to provide an apparatus for carrying out the chemical vapor deposition process.
To accomplish the first and other objects of the present invention, there is provided a method of performing a chemical vapor deposition process, whereby a process chamber is cleaned by introducing a cleaning gas including a fluorine radical into the process chamber. A wafer is then loaded into the process chamber. A film is deposited on the wafer by introducing a deposition gas into the process chamber, while preventing the deposition gas from flowing back toward a cleaning gas supply line.
To accomplish the second and other objects of the present invention, there is provided an apparatus for carrying out a chemical vapor deposition process, the apparatus having a process chamber in which the chemical vapor deposition process is carried out. A first supplier supplies a cleaning gas into the process chamber for cleaning the process chamber. A plasma device is installed between the process chamber and the first supplier, to excite the cleaning gas supplied from the first supplier. A second supplier supplies a deposition gas into the process chamber, so as to deposit a film on a wafer. A mixer mixes gases supplied from the first and second supplier into the process chamber, and a mechanism is provided to prevent the deposition gas from flowing back toward the first supplier.
In accordance with the above-noted method and apparatus, when the film is being deposited on the wafer, the deposition gas is prevented from flowing into the cleaning gas supply line, so that particles are effectively reduced.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.